Does the 300 (on 07 to be specific) header really flow more than the 250. Does anybody have any objective proof other than sticking a finger in the hole?

Mine is a 351 09 KLX with about 10 miles on the engine with stock exhaust and Dynojet. I want a quiet pipe hence the stock set up for now. From other posts it seems my best bet to a relatively quiet pipe is with the 300 header and exhaust (with changable tips).

So I found an 07 300 header for sale, but the owner says it doesn't flow more than the 250, but he will sell it to me anyway if I really want it. How honest is that, now? He bought a 4 stroke works header.

 

LOL

I think the size difference is negligible, but it has been argued a few times on here. If you want to end up using the 300 muffler, I think you need the 300 header, or a header the same length as the 300 header (the 250 header is shorter if I remember correctly)
Dan

 

I have a KLX300 and a pre 2008 KLX250S headers at home.

They are both the same identical diameter. No difference.

The one from a 300 is little longer. -> With a muffler that's made for a 300 you must use a header from a 300. And vice versa.

There's absolutely no benefit in just going with the 300 header, other than it allows you to use a 300 muffler.

--
Mikko

 

The difference is in the size (diameter) of the joint with the muffler. They are otherwise identical.

 

Not wanting to be an **** here, but why on earth do questions like this need to be asked after 10 miles?
Almost as bad as "got my new KLX today, rode it to the end of my street, it's the best bike ever"

 

The 10 mile thing was coincidental. I've been searching for the answer since I got my bike. I finally found a header for sale (nothing on e-bay for two months) and when the guy said they don't flow more I wanted to find the answer, and thanks, posters, I got it.

 

A little off topic, but related. I want to use the KLX 300 muffler. Are there other recommended after market headers that use that muffler that will flow more than stock and what gains or benefits would I receive in terms of power delivery.

 

You might get a Powerbomb or Megabomb made for the 300. I put one on my stock bike with an aftermarket slip-on and it did add some low end.

 

I could be wrong but I think the most constriction on the 250 is the muffler. Mod that just a little bit and you should have a muffler = to the 300.

What do you value more? Quiet pipe OR pipe & header that flow the most (louder)?